Reliable personal authentication is becoming increasingly important. For example, transactions that rely man-made personalized tokens or other identifying instruments to verify the identity of an individual are being targeted by criminals to engage in identity theft. Traditional security measures rely on knowledge-based approaches such as passwords and PINs or on token-based approaches such as swipe cards and photo identification to establish the identity of individuals. Despite being widely used, these are not very secure forms of identification. It is estimated that hundreds of millions of dollars are lost annually in credit card fraud in the United States due to consumer misidentification and identity theft. Biometrics offers a reliable alternative. Biometrics is the method of identifying an individual based on his or her physiological and/or behavioral characteristics. Examples of biometrics include fingerprint, face recognition, hand geometry, voice, iris, and signature verification. Biometrics may be used for immigration, airport, border, and homeland security. Wide scale deployments of biometric applications such as the US-VISIT program are already being done in the United States and elsewhere in the world.
Despite advances in biometric identification systems, several obstacles have hindered their deployment. For example, for every biometric modality there may be some users who have illegible biometrics. For example a recent NIST (National Institute of Standards and Technology) study indicates that approximately 2 to 5% of the population does not have legible fingerprints. Such users would be rejected by a biometric fingerprint identification system during enrollment and verification. Handling such exceptions is time consuming and costly, especially in high volume scenarios such as in retail stores where thousands of transactions may be subject to authentication each day. Using multiple biometrics to authenticate an individual will alleviate this problem; and, using multiple biometrics in a data fusion logic process may achieve a quicker means of acquiring an accurate identification match.
Furthermore, unlike password or PIN based systems, biometric systems inherently yield probabilistic results and are therefore not fully accurate. In effect, a certain percentage of the genuine users will be rejected (false non-match) and a certain percentage of impostors will be accepted (false match) by the system.